The invention relates to a wheel system for use in air handling units, such as for a rotary heat exchanger or for dehumidification purposes, having an improved construction in the area of the hub joint assembly, the spoke design, the rim joint assembly and the combination of hub, spoke and rim assembly.
Current designs for the construction of the such rotary wheels inherently have many shortcomings. For example, mechanical endurance or product fatigue life is adversely affected by the transfer media working loose in the support structure and self-destruction against the stationary casing frame. In addition, product operating efficiency or performance is adversely affected. Special tooling is required during field installations that is best suitable for factory assembly due to a general lack of proper access to the wheels. Further, retrofit work on large air systems in critical areas such as hospital operating rooms, etc., can cause long shut down times. There are cost savings associated in an improved construction that allows for reduced installation labor and travel expenses. In addition, improved efficiency increases energy savings per user and longer product life reduces maintenance costs and future repair expenses. The present invention described herein is suitable for use in field installations of new equipment or for retrofit of old units.
Typically, the rotary wheel or xe2x80x9cThermo-Wheel Systemxe2x80x9d includes a rotor support structure, a drive base assembly and an air seal assembly. The key components consist of aluminum and rubber extrusions joined together with mechanical bonds, welding or bolting together.
The invention may be described as a rotary wheel system comprising a rotatable frame having a rotation axis, and a media matrix comprising a plurality of removable, interchangeable media segments.
The rotatable frame includes a hub assembly having a circular portion, and a plurality of spokes radially extending from said circular portion of the hub assembly, in between which each media segment is located.
Each spoke generally has an I-beam cross-section with two spaced-apart flanges perpendicular to a center section. Each spoke is formed of a primary spoke and a secondary spoke, separated along the center section, typically proximate the secondary spoke flange. Each primary spoke is fixed at one end to hub joint means for fastening the primary spoke to a portion of the circular portion of the hub assembly. Fastening means for joining each secondary spoke to each respective primary spoke are provided.
The invention also includes a rim assembly, which includes a plurality of rim segments. Rim joint fastening means for fastening each end of each rim segment to one of the plurality of spokes are also provided.
Each media segment is compressed within a generally pie-shaped formed portion of the rotatable frame bounded by the hub assembly, two radially extending spokes and one of the rim segments.
Each primary spoke has two spaced-apart opposed recesses running longitudinally substantially from the one end of the center section of the primary spoke fixed to the hub joint means to an opposite end of the center section of the primary spoke.
Each primary spoke further comprises two spaced-apart slots at the opposite end of the center section, each slot having a fastening member fixed therein aligned so as to engage with the rim joint fastening means.
The inside surfaces of each side of the primary and secondary spokes include serrations against which segments of the media matrix is compressed for preventing movement of the matrix segments during operation of the rotary wheel system. Each segment of the media matrix is compressed so as to be squeezed within each recess of the primary spoke bounding and facing the segment of the media matrix.
The hub assembly includes a shaft portion and the circular portion has a continuous surface across which the hub joint means interfaces. The hub assembly shaft portion and circular portion may be comprised of two spaced-apart circular discs, an outer surface of each disc being circular, the hub joint means interfacing with said outer surfaces and extending from one disc to the other.
The hub joint means comprises a spoke support structural member. The spoke support structural member has a groove portion at an approximate center of said spoke support structural member. The groove portion extends longitudinally across the spoke support structural member and receives the primary spoke, which is fixed thereto.
The spoke support structural member further has an arcuate surface for interfacing with the circular portion of the hub assembly. The arcuate surface has an alignment groove in which two spaced-apart alignment pins, each fixed to the circular portion of the hub assembly extend into the alignment groove. The spoke support structural member is fastened to the circular portion of the hub assembly.
The fastening means for joining each secondary spoke to its corresponding primary spoke is typically a plurality of spaced-apart bolts secured from a top of the flange for the secondary spoke through said flange into the center section of the primary spoke.
Each rim joint fastening means comprises a spoke rim bracket member, which has a surface interfacing with the opposite end of the center section of a spoke. The spoke rim bracket member has two spaced-apart apertures into which bolts are inserted for fastening the spoke rim bracket member to the fastening members in each center section slot.
Each rim joint fastening means further comprises a pair of rim segment retaining brackets, each being generally L-shaped with two spaced-apart apertures on one of a leg of each of the L-shaped rim segment retaining brackets through which fasteners are inserted to secure one end of one of the rim segments to the spoke rim bracket member and to secure one end of an adjacent rim segment to the spoke rim bracket member.
Each rim joint fastening means further comprises a longitudinal semicircular recess on two corners of each spoke rim bracket member on the spoke side of the spoke rim bracket member, a circular rod positioned in each recess, and two spaced-apart threaded holes in each rod. Each spoke rim bracket member further has four spaced-apart diagonal bores, two on each side of the each spoke rim bracket member, the bores aligned to enter the semicircular recesses. Fasteners which secure each end of adjacent rim segments to the spoke rim bracket member are inserted through the diagonal bores and threaded into the threaded holes in the circular rod. The four spaced-apart diagonal bores would typically extend through the spoke rim bracket member at an angle of from about 25 degrees to about 30 degrees relative to each end of the adjacent rim segments.
Each spoke rim bracket member also has a longitudinal recessed portion of sufficient depth such that heads of the bolts fastened into the center section of the spoke underlie each end of adjacent rim segments attached to said spoke rim bracket member. In addition, the spoke rim bracket member further has an intermediate recessed portion perpendicular to the longitudinal recessed portion, the intermediate recessed portion being of sufficient depth so as to underlie belt drive grooves in each adjacent rim segment attached to the spoke rim bracket member.
The leg of each L-shaped rim segment retaining bracket with the two spaced-apart holes through which fasteners are inserted to secure the one end of one of the rim segments to the spoke rim bracket member and to secure the one end of the adjacent rim segment to the spoke rim bracket member further has a recessed portion of sufficient depth so as to underlie one or more belt drive grooves in each adjacent rim segment attached to said spoke rim bracket member.
Each rim segment is arcuate-shaped with a generally C-channel configuration, and each rim segment further has one or more belt drive grooves approximately centered and extending from one end of each segment to the another end of said segment.
The spoke rim bracket member further has cut-out portions on each end of said spoke rim bracket member into which a portion of each outside leg of the generally C-shaped channel configured rim segment depends.
The rim assembly further comprises a generally C-shaped channel member extending generally along the length of each rim segment in an underlying relationship to the rim segment and its one or more belt drive grooves. The generally C-shaped channel member has a flat surface against which the media segment is compressed.
In an alternative embodiment, the shaft portion may be a detachable split shaft mechanically coupled to each side of the circular portion of the hub assembly.
The outside surfaces of each side of the primary and secondary spokes may also include serrations which causes a higher resistance to air leakage from one air stream to the other as the spokes passes by a seal in the equipment housing of the wheel system.